| commit | 4224d81fae7bfce98629894d14f4644018037cfb | [log] [tgz] |
|---|---|---|
| author | Russ Cox <rsc@golang.org> | Fri Mar 20 00:06:10 2015 -0400 |
| committer | Russ Cox <rsc@golang.org> | Fri Mar 20 20:05:37 2015 +0000 |
| tree | a69bfb0356406df650405a15ceee342f33313549 | |
| parent | b115c35ee337ac6026539802d2ff085949dd1919 [diff] |
cmd/internal/gc: inline x := y.(*T) and x, ok := y.(*T)
These can be implemented with just a compare and a move instruction.
Do so, avoiding the overhead of a call into the runtime.
These assertions are a significant cost in Go code that uses interface{}
as a safe alternative to C's void* (or unsafe.Pointer), such as the
current version of the Go compiler.
*T here includes pointer to T but also any Go type represented as
a single pointer (chan, func, map). It does not include [1]*T or struct{*int}.
That requires more work in other parts of the compiler; there is a TODO.
Change-Id: I7ff681c20d2c3eb6ad11dd7b3a37b1f3dda23965
Reviewed-on: https://go-review.googlesource.com/7862
Reviewed-by: Rob Pike <r@golang.org>
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